Exxon surpasses Apple as world's most valuable company

Apple's run as the world's most valuable company is over, at… (Eric Risberg / Associated…)

The king is, well, not exactly dead. But Apple's stock has taken a pretty serious knee-capping this week, compounding a slide that began in September. And as a result, Exxon is once again king of the stock markets.

On Friday, Exxon became the world's most valuable company as Apple's stock fell in midday trading $10.46, or 2.32%, to $440.04.

In midday trading, Exxon boasted a $417.59 billion market cap; Apple's was $412.36 billion. The days of August, when people were debating whether Apple had set the record for the most valuable company in history, now seem like a dream from another era.

Apple's stock has now dropped 37% since its September high of $702.10. In just the last two days, the stock is down 14.6%.

The question now facing Apple investors is just how far the stock can tumble before it reaches equilibrium.

While there has been a touch of schadenfreude as people watch analysts rein in bullish estimates and large Apple shareholders count their losses, it's worth noting that the company's stock is one of the most widely held in the world. It might be hard to find anyone with a pension fund or 401(k) who has not at least been affected a little by Apple's stock decline.

Investors will now likely be waiting anxiously to see if the stock could approach the next psychological barrier of $400 per share.

Beyond that is another interesting milestone to note: Tim Cook's massive stock grant. When Cook officially replaced Steve Jobs as CEO in August 2011, the company awarded him 1 million shares of restricted stock units. Their estimated value at the time was $383 million, which assumed the grant price was about $383 per share.

The RSUs are set to vest in two chunks: Half on Aug. 24, 2016 and half on Aug. 24, 2021. That means Cook can't sell them until those dates. RSUs are not options, which come with a strike price. That means that no matter what the ultimate price of the stock, Cook would make money when he sells.

Still, if Apple has lost all the value Cook had created for investors since he was hired, investors might be less than pleased.